RF power amplifiers are used in a variety of applications such as base stations for wireless communication systems, etc. RF power amplifiers typically amplify a high frequency modulated carrier signal with frequencies range of 400 megahertz (MHz) to 60 gigahertz (GHz). A baseband signal that lies in frequency ranges below the carrier frequency, e.g., in the range of 100-500 MHz, is used to modulate the carrier signal thereby conveying information.
Many RF power amplifier designs utilize a semiconductor based integrated circuit as the amplification device. Examples of these switching devices include power transistor devices, such as a MOSFET (metal-oxide semiconductor field-effect transistor), a DMOS (double-diffused metal-oxide semiconductor) transistor, a GaN HEMT (gallium nitride high electron mobility transistor), a GaN MESFET (gallium nitride metal-semiconductor field-effect transistor), etc.
In addition to the power transistor device, many RF power amplifier designs include one or more impedance matching networks integrated into the amplifier package. An output impedance matching network can be provided at the output side of the package between the transistor output terminal (e.g., the drain) and the package second RF lead. Correspondingly, an input impedance matching network can be provided at the input side of the package between the transistor input terminal (e.g., the gate) and the package First RF Lead. A conventional function of these impedance matching networks is to match a characteristic impedance of the amplifier device (e.g., the input impedance or the output impedance) to a certain value for optimum power transfer. In addition, these impedance matching networks can be configured to filter higher order harmonics of the carrier signal to improve efficiency.
One drawback of known RF amplifier package designs is that a substantial amount of package area must be used between the die and package leads to accommodate passive components such as chip capacitors for the impedance matching networks. This space requirement moves the transistor die further away from the package lead, which results in longer bond wires. With a more complex impedance matching network, multiple bond wires that represent different electrical nodes are densely populated in the package. This causes unwanted parasitic effects including added resistance and mutual coupling which degrades the performance of the impedance matching network.